Will older films be produced on blu-ray or HD?

All movies that were originally film have a higher resolution that 1080p, whether they are introduced in 1080 is up to the company that owns the rights to the movie. The actual quality of the copy is determined by the quality of the transfer as the original film quality is superior to 1080P. I would guess that if HD or Blue-ray become the standard, then yes all films will eventually be available in that format. Taking into account that the quality of the transfer just like in audio is in the hands of the engineer.
Some will be great and some will be inferior.

yes, but depending on the age and condition of the original materials...and the post production.....they may not look significently better. some films look as good as they are going to..period.

Just like they colorize many old B&W movies, they may someday try to computer re-engineer old movies to something sharper than it appeared originally. It may not be technologically available as we speak, but in a few years who knows. Might be the only choice if regular DVD is discontinued someday.

I am surprised they did not digitally remove the wires in that Matrix example..

Same for the cost. Digital effects use to be very expensive; now any Joe/Jane with a Apple PC can produce better effects than George Lucas could 5 years ago.

You would be suprised at the quality and condition of some of the older films from the 40s, when and if they are transfered to HD they will be superior to the current dvd format.